Improvement in head-blocks for saw-mills



C(illntrd tapes @sind @imita Lettws Patent No. 93,724, cla-ted August 17, 1869.

IMPROVEMENTIN HEAD-BLOCKS FOR SAW-MILLS.

The ySchedule referred to in these Lettere` Patent and making part of the same.

To all whom it may concern:

Beit known that I, C. LEFFLNGWELL, of Clarksburg, in the county of Ross, and 'State of Ohio, have invented a new and useful Improvement in Head- Blocks for Saw-Mills; and that the following description, taken in connection with the accompanying drawings, hereinafter,relerred to, forms a full and exact specification of the same, wherein I have set forth the nature and principles of my said improvement, by which my invention may be distinguished from all others of a similar class, together with such parts as I claim, and desire to have secured to me by Letters Batent.

y This invention relates toa new and improved head-` block tor saw-mills, and is an improvement on a headblock for which Letters Patent were granted to me, bearing date J uly-3, 1866,

The invention consists in a peculiar means employed for holding the knees in position, themechanism for moving the knees, and stops arranged in a novel wa'y for regulating the movement of the knees in order to saw boards and planks of different thicknesses, as may be required.

In the accompanying sheet of drawings- Figure 1 is a vertical section of my invention, taken in the line x a, fig. 4.

Figure 2, a vertical seetion of the same, taken in -the line y y, iig. 4.

Figure 3, a side View of one ofthe knees and a portion ofthe head on which it works.

Figure 4, a plan or top view ofthe wholedevice.

Figure 5, a'horizontal section of a portion of the same, taken in the line z s, tig. 1.

Similar letters of reference indicate like parts.

A represents the log-carriage, and

B B, head-blocks, permanently secured thereto in any proper manner.

These blocks are of I -forln in their transverse section; and to one side of the same there are placed. racks J, which are provided with vertical teethl a.

These racks are allowed to slide' freely at the sides of the blocks, and are retained in position at their lower edges by guides b b', and at their upper edges by the bases o ofthe knees K, theI lower edges of the bases at one side extending under the upper flanges d of thebloeks, and bearing against the rack-bars, as shown at e in iig. 1.

'.lo each base, c, of the knees there is attached by a pivot, a pawl, L, and these pawls have each a plurality of edges f f f, one a triie in advance of the other, asv

shown clearly in g. 2, in order 'to admit of the racks engaging with the pawls without any lost motion.

These pawls have springs g, acting upon them to keep them in contact with the racks, but the pawls may, when desired, be thrown ont from the racks by means of cranks or eccentrics on vertical shafts, It, in the bases.

The pawls may be arranged in -pairs on studs, each pair being provided with a crank, h, sothat one set may be held ont of gear while the other is in use, or, if desired, both sets may be used at the saine time.

To eac'h knee K, at one side, there is attached a lever, M, having an eccentric, i, on its lower end, against which the upper arms ,of bent or right-angular levers N are made to-bear under the influence oi' springs j. (See ig. 3.) Y

The lower arms of these levers have sockets L attached to or formed on them; and through these sockets fixed bars O, which are attached to the sides of the head-block, pass.

By means of the springs j, the lower end of the lever N is pressed forward, forcing the sockets It to gripe the bar O, holding .the knees iirmly in place.

By depressing the upper arms of the levers by means of the eccentric levers M, the sockets k are released from the bar O, so that the knees may be moved in either direction upon the head-blocks.

lhe racks J are operated as follows:

l l is a sliding bar, placed underneath the blocks B B, and fitted in recesses in thecross-bars-of the logcarriage. This bar P is connected by arms lto one end of bent or right-angular levers Q,secured to the under sides of the blocks, the opposite ends of said levers being connected by rods 'm to the racks J. The bar P is connected at one end to a lever, R, by moving which the bar l) is operated, and consequently the racks, and from the latter the knees K, thc knees being moved in one direction only, that indicated by arrow l, in order to feed the log to the saw, as the teeth of the racksv catch or engage with t-he pawls,

when the former are moved in the direction of arrow vthe pressure of the sockets lo on the bars O.

The' extent of the movement of the racks J is an important feature, as by that the thickness of the lboards or planks to be sawed is determined.

The length of the movement of the racks is controlled by stops band n, the former having been previously referred to as guides. The latter are adjustable, being securedto the blocks by screws o. The excess ofthe length of the distance between the inner edges of the stops b n (see iig. 2) over the length of the racks J is equal to the setting movement of ythe knees, and consequently equal to the width of the boards or planks to be sawed, and the .width may be varied as desired by adjusting the stops n.

By placing the stops b n at the extremities of the setting-apparatus, the lostr motion caused by the diferent weight of the logs to be sawed is equalized; that is tosay, by operating the lever R, and through its connections thc knees, the latter are moved, feeding the log forward until the rack at the lighter end ofthe log strikes the stop b upon the head-block, thereby reaching the limit of its throw, while the rack at the heavier` end ofthe log has not, through different causes, reached the other stop.

It' the log should be sawed in this position, the lu1nber would necessarily be thicker at one end than at the other. It is, therefore, necessary that the heavier end should be fed forward to overcome this diiculty, which is accomplished by continuing the pull upon the lever R, the last motion of the lever-connections in A the rack already in position permitting this extra pull,

continuing the motion produced thereby to the level'- conneetions of the rack at the heavier end of the log. '.lhe stops n limit the backward throw of the racks.

n, the whole constructed, arranged, and operating substantially as and for the purpose specified.

C. LEFFINGWELL.

W itncsses:

J. Bnoron'rox, N. M. HUn'rr.

crank-shafts h, fixed stops b', and the adjustable stops Y 

